Aformer is an object, such as a template,gauge orcuttingdie, which is used to form something such as aboat'shull. Typically, a former gives shape to a structure that may have complexcurvature.
A former may become an integral part of the finished structure, as in an aircraftfuselage, or it may be removable, being used in the construction process and then discarded or re-used.
Formers are used in the construction of aircraftfuselage, of which a typical fuselage has a series from thenose cone to theempennage, typically perpendicular to thelongitudinal axis of the aircraft. The primary purpose of formers is to establish the shape of the fuselage and reduce the column length of stringers to prevent instability.[1] Formers are typically attached tolongerons, which support the skin of the aircraft.
The "former-and-longeron" technique (also called stations and stringers) was adopted fromboat construction,[2] and was typical oflight aircraft built until the advent ofstructural skins, such asfiberglass and othercomposite materials. Many of today's light aircraft, andhomebuilt aircraft[3] in particular, are still designed in this way.
A former may instead be a temporary shape over which a structure is built, the former subsequently being discarded in whole or part, as follows:
